Pattern cam-disk retaining means for zigzag sewing machines



Fig 2 B INVENTOR. Charles R. Odermann FTTORNEY R O F 5 ms N mw G 9 mm e a .51 W Emm D W O E0 3 W R l m m G. 7 mm 4 3 m m m F m 4% P Aug. 25, 1959 WITNESS MW United States Patent M zpolms PATTERN ,e M-nisK, FOR .ZIGZAG' SEWING MACHINES Gharles mi fldermannj Milfoi'dgConn assignor t" The Singer Mannfacturing Company;TEliZabetMNJg. a cmeporationeofiNew-Iersey i This "invention relates to- 'zigzag" "sewing machines;- and t more particularly-to"- an =imprbved means for -mounting "and retaining--apattern cam-diskon 'the'end of the camshaft' of a" zigzag" sewing- -maehine.

shaft having a'squard portion' whichmntersa squared aperture centrally providedflin 'aipaittem cam-disk, the

.pattern cam-disk being held;to the. cam-shaft"hy'ya nut -wh-ich is screwed to the threaded endof the shaft. While arrangements similar to those described aboverhave been :quite: satisfactory, it has been:founddesirabledo provide .a mechanism which will permit one pattern cam-disk to be removed easilyand' quickly'-and"replaced by another Lpattern cam-disk. .Also..it..is..desirahle to perform this operation with the minimum chance of dropping the parts used to secure the pattern cam in place. Therefore, one of the primary objects of the present invention is to provide an improved retaining means for mounting a pattern cam-disk on the end of the horizontal cam-shaft of a zigzag sewing machine.

Another object of the invention is to provide an improved retaining means for the pattern cam-disk of zigzag sewing machines in which there is little or no danger of dropping the parts thereof when one pattern cam-disk is removed and replaced by another.

A still further object of the invention is to provide an improved means for mounting a nut on the end of a hollow shaft.

Other important objects of the invention will be apparent from the following detailed description and appended claims, and a preferred embodiment of the invention is illustrated in the accompanying drawings where- 111:

Fig. 1 is a fragmentary elevational view of a zigzag sewing machine embodying the present invention;

Fig. 2A is a vertical sectional view taken substantially on the line 22 of Fig. 1;

Fig. 2B is a view of a portion of the structure shown in Fig. 2A and similar thereto except that external and internal screw threads, which were shown engaged in Fig. 2A, are shown disengaged in Fig. 2B. Also some elements, which appear in cross section in Fig, 2A, appear in elevation in Fig. 2B and vice versa; and

Fig. 3 is a development showing 360 of the external threads carried by one of the elements shown in Figs. 2A and 2B.

Referring in more detail to the drawings, the invention has been shown in Figs. 1 through 3, as embodied in a zigzag sewing machine of a type similar to that shown in US. Patent No. 2,756,703, to which reference should be had for more details of the construction of the sewing machine.

The portion of the sewing machine illustrated in the present drawing comprises a hollow standard 16 forming part of an open-topped bracket-arm 17, which is provided with a cover 18. A main shaft 19 is rotatably Patented Aug. 25, 1959 journalednin bearings supported byuthe -bracket-arm= 17. The main shaft 19* carries? a, combination hand-wheel and driving" pulley 21; and: ra wormewheel. 22. r The wormwheel 22 "drives 'att a muchl ireducedispeed, aworm-gear 5 -23 -securedona cylindricalwcam-shaft 24.: rotatably cartied in bearings, onerofswhichvis indicated .by thernumetal 26.

The cam-shaft 24, at a location spaeed from theend "thereof, iszprovidedrwith a cam receivingor support memint the; iform of at eirculaniflange 27 :from the front -taceiofl'iwhich protrudes arcam registering'dog-pin. 28 which extends parallel. to: :the' axis of the cam-shaft 24. I The front: end'imember' or terminal head 29: of the camshafti 24;: at a 1 locations between said flange 27 and the 15.sfront end' ofwthe shaft: isenlarged and provided'wwith arcentrallya located axially extending :cylindrical hole or arapertures'3l =The' peripheryof the terminal' head=29=is provided with a 1 holding device-ormeans in theform-f of externalphi gbpitch multiple i-threads 32, a "development :ofi theseTthreadS being illustratediin Fig. 3. The=multiple .it hreads 32 comprise -three separate threadaspirals indi- 'cated by the *numerals? 3.6,. 372 and? 38. The .fl'H'BEIClSP-llfi]. .'36'-begins: at amexternal'point 46 and ends at ari internal 1 point 56. The thread-spiral '37" begins i ate an external point 1. 47 and: ends a at *an" internal; point 57. Also; the 1 ithreadaspiral: 38" begins at an external "point 48 and'ends at an internal point 58. aItawillrbenotedthat each of the r thread-spirals encircles approximately 5'40 F degrees of the head 29. In other =words,::each'zthread spiralsexttends fapproxirnately oner'and; one-half "times around the head 29.

The terminal head 29 of the cam-shaft 24 is fitted with a cylindrical thumb member or nut 61 having a holding device or means in the form of an internal highpitch, multiple threads 62, and an external roughened rim 63. The internal multiple threads 62 have three thread-spirals which have the same pitch as the threadspirals 36, 37 and 38, and thus the thumb-nut 61 may easily and rapidly be screwed on and oif the threads 32 of the terminal 29. The thumb-nut 61 also has a cylindrical pilot-stud 64 which extends concentrically from the bot tom of the thread cavity of the nut 61 and the stud is of such size as easily to enter the hole 31 in the head 29. Reference to Fig. 2B shows that the pilot-stud 64 extends beyond the internal threads 62 and also a considerable distance beyond the main body of the thumbnut 61. Because of this it is possible to disengage the internal threads 62 from the external threads 32 and still have the thumb-nut 61 supported, by means of the pilot-stud 64, from the end of the cam-shaft 24.

It will be understood that the purpose of the cam-shaft 24, the flange 27, the dog-pin 28 and the thumb-nut 61 is to mount or support a pattern cam-disk 66. The disk 66 has a central aperture 67 whidh fits over the head 29 and a hole 68 which receives the dog-pin 28.

The edge of the cam-disk 66 is, in a well known manner, engaged by a cam-follower 71 supported by an arm 72 of known construction.

In operation, the subject device functions in the following manner. If it is desirable to replace the pattern camdisk 66, the thumb-nut 61 is grasped by the thumb and forefingers. Because of the multiple threads 32 and 62 it is possible to disengage the threads 62 from the threads 32 by a little more than one complete revolution of the nut 61. This requires the fingers to make only two turning movements. Disengaging threads 62 from threads 32 does not entirely remove the nut 61 from engagement with the head 29. This is because disengagement of threads 62 from threads 32 does not remove the free end of the pilot-stud 64 from the hole 31. The engagement of the pilot-stud 64 in the hole 31 prevents the thumbnut 61 from falling and striking and marring the highly polished 'bed plate of the sewing machine. When ready the operator grasps the thumb-nut 61 and pulls the pilotstud 64 from the hole 31. Then the cam-disk 66 is removed and replaced by another cam-disk (not shown). Thereafter, the pilot-stud 64 is inserted into the hole 31 and the thumb-nut 61 screwed on the terminal head 29. Placing the pilot-stud 64 in the aperture 31 aligns the threads 62 with the threads 32 and thus facilitates starting the nut as it is screwed to the head 29.

Having thus described the nature of the invention, what I claim herein is:

1. Means for holding a pattern cam-disk on the camshaft of a sewing machine, said means comprising a cylindrical end-portion on said camshaft, said end-portion having a coaxially extending unthreaded hole, external screw threads formed on the surface of said end-portion, and a thumb-nut adapted to be mounted on said endportion, said thumb-nut having an internal cavity, internal screw threads formed in the internal cavity of said thumb-nut and designed to engage the external threads formed on the surface of said end-portion, an unthreaded pilot-stud formed on said thumb-nut and having a surface defining a cylinder positioned coaxially with respect to the internal threads of said internal cavity and said pilot-stud extending beyond the internal threads and also beyond the end of said thumb-nut, said pilot-stud being long enough to support said thumb-nut on said end-portion when said internal threads are completely disengaged from said external threads, and said pilot-stud acting as a guide for easy engagement of said internal threads and said external threads when attaching said thumb-nut to said end-portion.

2. Means for holding a pattern cam-disk on the camshaft of a sewing machine, said means comprising a cylindrical end-portion on said camshaft, said end-portion having a co'axially extending unthreaded hole, high-pitch multiple external screw threads formed on the surface of said end-portion, and a thumb-nut adapted to be mounted on said end-portion, saidthumb-nut having an internal cavity, high-pitch multiple internal screw threads formed in the internal cavity of said thumb-nut and designed to engage the external threads formed on the surface of said endportion, said high-pitch multiple threads making it possible completely to screw and unscrew said thumb-nut by approximately one complete turn thereof, an unthreaded pilot-stud formed on said thumb-nut and having a surface defining a cylinder positioned coaxially with respect to the internal threads of said internal cavity and said pilot-stud extending beyond the internal threads and also beyond the end of said thumb-nut, said pilotstud being long enough to support said thumb-nut on said end-portion when said internal threads are completely disengaged from said external threads, and said pilot-stud acting as a guide for easy engagement of said internal threads and said external threads when attaching said thumb-nut to said end-portion.

References Cited in the file of this patent UNITED STATES PATENTS 291,945 Schwarzwalder Ian. 15, 1884 2,178,160 Berry Oct. 31, 1939 2,310,176 Hale Feb. 2, 1943 2,756,703 Perla et al. July 31, 1956 FOREIGN PATENTS 744,172 France Jan. 21, 1933 

